Raspberries are grown for the fresh fruit market and for commercial processing into individually quick frozen (IQF) fruit, purée, juice, or as dried fruit used in a variety of grocery products such as raspberry pie. Traditionally, raspberries were a midsummer crop, but with new technology, cultivars, and transportation, they can now be obtained year-round. Raspberries need ample sun and water for optimal development. Raspberries thrive in well-drained soil with a pH between 6 and 7 with ample organic matter to assist in retaining water.
While moisture is essential, wet and heavy soils or excess irrigation can bring on Phytophthora root rot, which is one of the most serious pest problems facing the red raspberry. As a cultivated plant in moist, temperate regions, it is easy to grow and has a tendency to spread unless pruned. Escaped raspberries frequently appear as garden weeds, spread by seeds found in bird droppings.
The fruit is harvested when it comes off the receptacle easily and has turned a deep color (red, black, purple, or golden yellow, depending on the species and cultivar). This is when the fruits are ripest and sweetest. Raspberry plants should not be planted where potatoes, tomatoes, peppers, eggplants, or bulbs have previously been grown, without prior fumigation of the soil. These crops are hosts for the disease Verticillium wilt, a fungus that can stay in the soil for many years and can infest the raspberry crop.
An individual raspberry weighs 3–5 g , and is made up of around 100 drupelets, each of which consists of a juicy pulp and a single central seed. A raspberry bush can yield several hundred berries a year. Unlike blackberries and dewberries, a raspberry has a hollow core once it is removed from the receptacle.